The couple inside the house, Linda and Jeff Dolloff, both were badly wounded. She had been shot in the midsection with a handgun. He had been beaten nearly to death with a baseball bat.

Both would survive, although the husband had no recollection of the event. What came next would change their lives forever. After an investigation, police said the wife, a yoga instructor, had tried to kill her husband and then shot herself, as part of a cover-up. She was charged with attempted murder and other crimes and faced up to 30 years in prison.

Forensics Expert Assesses Gun Evidence

Watch the full story tonight on "20/20" at 10 p.m. ET

As Linda Dolloff's trial began, however, prosecutors knew they had several problems. There were no eyewitnesses, there was no confession and the defendant looked like anything but a would-be killer.

The prosecution's case would have to be built on cutting-edge forensic evidence and a persuasive story about why Linda Dolloff might have wanted her husband dead.

"I think that juries would prefer to have an eyewitness, or videotape," Cumberland County District Attorney Stephanie Anderson said, "but a circumstantial case can be just as strong as a case with an eyewitness."

Anderson and her team plunged into the task of proving their case against Linda Dolloff. The weapons used on the Dolloffs that night, they argued, indicated that the attacks were not the work of a stranger unfamiliar with the home.

The gun used to shoot the wife, now 48, belonged to her husband, for example.

"The gun's not foreign to the scene, the baseball bat's not foreign to the scene, and they're not weapons of opportunity," Maine State Police Det. Bill Ross said. "These weren't things that were just left out in the open."

Crime Scene Video of Linda Dolloff

The bat, Ross said, was "tucked away behind some machinery" in the garage. There were two other baseball bats in the house that were more easily accessible, he said.

DNA Evidence on Bat

There was important solid evidence on the bat handle.

"I was able to find Linda Dolloff's DNA on the grip portion of the baseball bat," said Christine Waterhouse, a forensic DNA analyst at the Maine State Crime Lab. "There was some human bloodstains on the grip area that came back as matching Linda Dolloff."

But the defense had an explanation for the blood on the bat.

"Her explanation being," Anderson said, "that after she got shot, you know, she's in there crawling around and, you know, she may have touched it."

Linda Dolloff Case: Who Shot the Gun?

Dan Lilley, who served as Linda Dolloff's defense attorney, said, "The bat was found at the foot of, on the floor, at the foot of the bed, near the blood.

"And she indicated that she went around the end of the bed, to find Jeff, and she ran into, or hit things on the floor. We believe that she hit the bat."

The other weapon, the gun used on Linda, was found on the second-floor landing.

Ross, the detective, said, "It was kept in Jeff Dolloff's dresser drawer. And this was the gun that was also used to shoot -- that Linda Dolloff received the gunshot wound from."

But Lilley told "20/20" that the wife, who is right-handed, would have had a hard time shooting herself in her right hip area, where bullet fragments lodged.

Anderson countered that Linda used a two-handed grip.

"The fact that the bullet wound was on her right side, I believe she had the two-hand hold," Anderson said. "She used her dominant hand to steady the gun, and she used her left hand to pull the trigger -- I mean it doesn't make sense that you'd do this, you would go across your body."

Linda Dolloff denied she had shot herself.

"To me, that is the most ridiculous part of the story," she told ABC News. "I find it absurd. I don't know how many people could emotionally get themselves into a place where they could physically do that. I don't ever see myself getting into a position where I could actually point a gun at myself and pull the trigger. No."

Lilley said the evidence ruled out her having shot herself.

"We measured her arms, it's 18-and-a-half inches from the armpit to the center of her hand," he said. "And the gun is six or seven inches maybe ..."

Linda Dolloff said, "I'd be within two or three inches of my body. There would be blood in the barrel. There would be something called tattooing around the wound. There would be the burn marks on my shirt. There is no evidence of any of those, and my DNA is not on the trigger, and I have no idea [how] I could shoot myself if I did not pull the trigger."

Crime Lab Tests for Gunpowder

Prosecutors knew this would be a major part of Linda Dolloff's defense. So they sent the .22 caliber Ruger handgun and the shirt Linda was wearing that night to the Maine State Crime Lab for testing.

"The question was how far was that gun from her clothing when it was fired," said forensic firearms expert Kimberly Stevens, who worked on the case. The standard procedure, Stevens said, is to look to see if there's gunpowder on the shirt.

"If the gunshot wound was self-inflicted, then we're looking at a shot that would need to be fairly close-range, because someone's arm is only so far," Stevens said. "And that, there's a distance at which the powder should be transferred."

But Linda Dolloff was right: The gunpowder the state expected to find on the shirt was not there.

"I looked at it visually, under the stereo microscope, and there was no powder residue on the shirt," Stevens said. "And even though you get a muzzle flash, there was no singeing or burning of the material on that shirt."

That evidence suggested the gun was fired from too far away for Linda to have shot herself.

Linda Dolloff Case: The Lead Vapor Test

But the state was not ready to give up on its theory. Stevens said gunpowder can shake loose from clothing, so it doesn't always show up in tests. She decided on a second test, this time looking not for powder but for lead vapors.

"The lead vapor is very fine-particle, it gets embedded in the weave and it's not always easy to see," Stevens said.

But if there is lead vapor on fabric, she said, a chemical spray will turn it purple and visible to the naked eye.

"So having no powder is not unusual, and having vaporous lead is very significant," Stevens said.

Stevens had tested the shirt Linda Dolloff was wearing when she was shot for lead vapors. The results were unequivocal: vapors were embedded in the fabric.

Prosecutors told the jury gunpowder wasn't important, but lead vapors indicated the gun was fired at close range.

"It was anywhere between zero, above zero and 18 inches," Stevens said. "Anywhere in there the muzzle could've been and could easily be pulled by the person holding it."

Blood Stains

The prosecution had trouble with some of its other physical evidence, however. Surprisingly, Linda Dolloff didn't have much blood on her, even though the bedroom where Jeff was attacked was coated from floor to ceiling.

"She's got blood here, on her left cuff, a little streak, and she's got spatter under her right armpit," Anderson said. "I think it's consistent with a baseball stance and whacking somebody with it. ...

"How could she get those stains, but for the fact that she was whacking him with this baseball bat? There is no other explanation for that."

According to the prosecution's own expert, Det. Scott Gosselin, however, that is flat out wrong. Gosselin's official report, read aloud to the jury, said "no conclusion could be drawn from Linda Dolloff's clothing with regard to her involvement in the assault against Jeffrey Dolloff."

He found that the stains on Linda Dolloff could have come from her husband spitting or vomiting blood. But prosecutor Anderson still told the jury exactly the opposite in her closing argument.

What Officer Saw in Window

There was also the question of what the first officer to arrive on the scene, Sgt. Jim Estabrook, saw in one of the home's windows.

"I can see one person in the window," Estabrook radioed that night to the Cumberland County Sheriff's dispatcher. "We've got to get some eyes on the house..."

Dan Lilley said Estabrook's word were evidence of an intruder, a third person in the house.

Anderson acknowledged the officer probably did see someone.

"[Estabrook] never tried to hide the fact that he saw something that he believed to be a person. And we think it was a person. I mean, it's a total non-issue. We think it was a person, and that person was Linda."

Linda Dolloff Case: The Corinthians Document

Then the prosecution's case received a boost from the defendant's own words.

Linda Dolloff had said she harbored no hard feelings that her husband was about to bring a new woman into his life to enjoy the house the couple had built together.

"I was not desperate, no, I was not desperate," she said.

But is that the real Linda Dolloff? Perhaps some of the most damaging evidence police found in their year-long investigation was on her computer, in personal writing she called the Corinthians document. The document was named after a letter the apostle Paul wrote about unconditional love.

Her version is a series of journal-like entries written to her husband. They reveal a different, and very desperate, woman who was about to be abandoned.

"I have no choices, I'm going to sign [for divorce]," she wrote. "However, I'm so, so scared. ... I have nothing. I have no idea what will happen. I'll live one day at a time. The only thing I know for sure is that it will be extremely painful and difficult. ... One of the things that will be most difficult is to have someone else enjoying the fruits of our labor. ... Bottom line I cannot stay like this. ... I cannot eat. I cannot sleep. I cannot breathe, ... I'm in a place where I cannot sustain myself. I'm not Linda."

Anderson said, "She wasn't going to have her life. It was going to be a very different life for her. And the writings that were found in her room betray a woman that was absolutely desperate."

In the jury box, Linda Dolloff's private writings took on the weight of her own voice. She never took the stand, but the words on her computer may have explained the motive she denied having.

"The Corinthians document had a great impact on me," said one juror, on condition of anonymity. "She sounded very confused, and frustrated, and left out, pushed away."

The jury deliberated across a two-day period.

Click HERE to see video of jurors' reactions to the Linda Dolloff case.

Watch the full story tonight on "20/20" at 10 p.m. ET

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